The subject matter disclosed herein relates to a mixing device, and particularly to a mixing device having a plurality of mixing channels that each include unequal distinct lengths.
A gas engine burns methane to produce mechanical energy. During standard or normal engine operation, the gas engine produces exhaust gas with a relatively low concentration of methane (e.g., about 500 ppm), which is passed directly to a catalyst. The methane is generally converted or oxidized into carbon dioxide and water by the catalyst.
In the event the gas engine misfires, a fuel-air mixture having a relatively high amount of methane (e.g., about 45,000 ppm) is released from a cylinder of the gas engine, and travels into an exhaust gas manifold. As the methane is oxidized in the catalyst, a relatively high amount of heat is produced within the catalyst, due to the elevated amount of methane in the exhaust gas. Specifically, there is a possibility that the catalyst may experience elevated temperatures above 900° C., which adversely affects the mechanical stability of a catalyst washcoat. The elevated temperatures may also create sintering of precious metals in the catalyst, which may decrease the conversion efficiency of the catalyst. Moreover, the elevated temperatures may also cause the catalyst to melt, which can affect channel structure of the catalyst.
Various devices currently exist to mix two or more streams of fluid (e.g., gas or liquid) together. For example, if multiple liquid streams need to be mixed, an agitator may be provided to create additional turbulence. In another example, if multiple gas streams need to be mixed, a flow strainer may be provided to create turbulence. However, these approaches have several drawbacks. Agitators tend to mix the multiple liquid streams together in a horizontal direction, which requires a relatively large mixing chamber volume. In some circumstances, providing an agitator may not be possible, due to the limited amount of space available and packaging constraints. Also, flow strainers create a relatively large pressure drop, especially at higher flow rates. Moreover, in the event a misfire situation occurs, flow strainers do not usually uniformly mix the methane with the exhaust gas.